Understanding Map Scale

Understanding Map Scale

Understanding Map ScaleTo represent geographic features on a map, the features must be reduced in size. The extent of this reduction is expressed as the map scale. Map scale is a method for expressing how map distance compares to ground distance, or the distance on the surface of the earth. Because a map's scale determines how features are represented on the map, it also affects the overall interpretation of the map.How to Interpret a Map ScaleUnderstanding the scale of a map is important if you need to know the size of the land features represented on the map or the relative distances between them. A map scale uses a dynamic ratio, 1:x, where 1 represents map distance and x represents distance on the earth. Map and earth distance are always the same unit. For example, if you have a map scale of 1:63,360, one unit of measure on the map equals 63,360 units of the same measure in the real world. If 1 is in inches, so is 63,360. In other words, one inch on the map equals 63,360 inches on the earth.Large Scale vs. Small Scale... What's Bigger?You will commonly see references to two types of maps: large scale maps and small scale maps. A large scale map, such as a map of city streets or a building plan, covers a small area in more detail. A small scale map, such as a world map, covers a large area in less detail. Map scale is relative, so a scale of 1:63,360 may be a large scale map compared to 1:316,800,000, but is considered small scale when compared to a map scale of 1:7,920. Remember, the smaller the number, the smaller the area covered by the map, resulting in greater detail; the larger the number, the larger the area covered by the map, resulting in less detail.Information derived from:http://mapshop.esri.com/help/concepts_mapscale.htm